The new cultivar is the product of chance discovery. The new variety originated as a naturally occurring whole plant mutation of the unpatented ‘Storm Cloud’ variety of Agapanthus. 
The new variety was first observed by the inventor, Luen Miller, during July 2003, in Royal Oaks, Calif., and was selected in. the Fall of 2004.
Subsequent asexual reproduction of the new cultivar ‘MBNAGVAR18’ was first performed by division in Royal Oaks, Calif., during Fall of 2004. Access to all plants was restricted, as plants were kept in a location not open to the public. Through subsequent propagation, multiple generations have been reproduced, which have shown that the unique features of this cultivar are stable and reproduced true to type.